(i) Field of the Invention
The present invention relates generally to an apparatus for providing shreds of cheese, and more particularly to the use of extrusion apparatus for forming a plurality of shreds of cheese of predetermined size.
(ii) Description of the Prior Art
Shredded cheese, or cheese in the form of elongated shreds or other shapes, is used in the preparation of various types of food, e.g., pizza. It is generally preferable for certain markets that the shreds be of approximately uniform size and weight, and be on the order of one inch in length.
Cheese is generally manufactured in relatively large blocks and is cut for sale into smaller blocks or chunks of shapes and sizes selected according to consumer preference. In the past, attempts to produce shredded cheese by extrusion have not been entirely successful. One problem has been that variation in the rate of extrusion across the width of an extrusion die has caused lack of uniformity among the shreds. Another problem has been that working of the cheese during extrusion has caused maceration and oiling off. xe2x80x9cMacerationxe2x80x9d is a softening of the texture of the cheese due to a breakdown of the cheese structure. xe2x80x9cOiling offxe2x80x9d is a separation of oil from the other constituents of the cheese. Both are undesirable and inhibit the formation of desired shreds.
One patent which purported to solve this problem was U.S. Pat. No. 4,620,838, patented Nov. 4, 1986, by R. E. Miller et al. and assigned to Kraft, Inc. That patent provided an extrusion apparatus for forming a quantity of cheese into a plurality of approximately uniformly shaped pieces, e.g., relatively small shreds of predetermined configuration without substantial damage to the cheese due to working and pressure. The apparatus included one or more chambers for holding the cheese, the chamber having smooth longitudinal interior surfaces for slidably-engaging the cheese. At the downstream end of each chamber was a perforated area of a die plate. A ram was provided to force the cheese downstream of its chamber through the perforations or openings in the die plate to form a plurality of extrusions of predetermined cross section. A vertically-oscillatable cutter assembly was positioned downstream of the die plate adjacent thereto to cut through the extrusions at a predetermined frequency as they emerged from the openings in the die plate. This action divided each extrusion into a plurality of discrete segments, each having a predetermined dimension in the direction of extrusion.
Another patent was U.S. Pat. No. 4,111,087, patented Sep. 5, 1978, by R. R. Pankrantz et al. Although that patent was directed to a cheese packaging apparatus, it also included a cheese cutter which would only commence operation when a loaf, or a stacked layer of cheese, was properly located at the intake position of the cheese cutter. The cheese cutter was fed standard loaves of cheese by a conveyor which comprised of rotatable, but translationally-stationary, rollers. The cutter included a scalloped ram which laterally moved the cheese across the rollers through a vertical harp on to a platform. The platform was an elevator, which in its lowered position, formed a portion of an automatic wrapping machine. The scalloped ram had vertical grooves in it which received the vertical wires of the cutting harp. Engagement and disengagement of the harp wires by the grooves removed any excess cheese particles from the harp.
Still another patent was U.S. Pat. No. 4,318,321, patented Mar. 9, 1982, by D. N. DeMattes and assigned to Codal Management Limited. That patent provided apparatus for cutting a block of a soft, non-granular substance into a plurality of portions. The apparatus included a platen to receive a block to be cut. A drive was provided for advancing the platen from a starting position, in steps, to a fully-advanced position. A first cutter was provided for cutting into the block along the direction of advance of the block on the platen. A second cutter was provided for cutting the block in a direction transverse to the cuts which were produced by the first cutter. Operation of both the first cutter and the second cutter produced a layer of portions cut from the block. The drive was adjustable to set the size of steps in which the platen advanced, and thus controlled the thickness of the layer of portions produced. The block was divided completely into a plurality of layers, none of which had a thickness less than a predetermined minimum.
Yet still another patent was U.S. Pat. No. 4,782,729, patented Nov. 8, 1988, by E. R. Mathot. Although relating to an animal fibre cutting machine, this patent included features which could be applied to the shredding of cheese. The patentee provided an apparatus which included a frame. The frame included slicers which were carried by the frame to rotate for slicing the material into elongated strands which were fed along parallel paths of widths determined by spacing of the slicers. Rotary cutters were carried by the frame to rotate and intercept the strands which were fed along the paths, and for also cutting the strands crosswise thereof and at intervals which were predetermined by rotary spacing of the cutters. This formed the pieces having predetermined sizes. The slicer comprised an elongated shaft, with the slicer comprising a plurality of parallel slicer discs which were spaced apart along the length of the shaft. The cutter comprised an elongated shaft carrying the cutters which were spaced-apart circumferentially of the shaft. The slicer shaft, and the cutter shaft had generally-parallel axes of rotation. Further, the cutters typically extended helically along, and about, an axis which was defined by the cutter shaft, and were spaced below the level of the slicer means shaft, the two shafts extending generally-horizontally. A back-up roller was spaced from, and was parallel to, the cutter shaft so that tips which were defined by the helical cutters intercepted a cylinder which was defined by the outer surfaces of the back-up roller. The back-up roller typically had grooves that received the cutter tips as the roller and cutter shaft rotated. The back-up roller included gearing which was operatively-connected with the roller and cutter shafts to control synchronized rotation thereof. Also, a slot-roller was employed to have slots which were positioned to receive outer portions of the slicer discs as the discs were rotated, and also having peripheral teeth to engage and drive the strands.
In spite of these alleged improvements in apparatus for shredding cheese, problems still remained. One of the major problems was that some of the extruded cheese tended to fall below the extruder before the slicer could slice the extruded cheese, thereby not only wasting cheese, but also degrading the quality of the subsequently-shredded cheese.
Accordingly, one object of this invention is provide an improvement in an apparatus for the shredding of cheese.
A second object of this invention is to provide such an improvement wherein the shredder assembly may easily and rigidly be exchanged.
By this invention, a first improvement is provided in an apparatus for forming a block of cheese into a plurality of relatively small shreds. The apparatus includes an elongated cheese chamber having longitudinally-extending side and floor surfaces for slidingly-engaging the block of cheese, an extrusion grid plate at the downstream end of the elongated cheese chamber, and ram means for forcing the block of cheese in a downstream direction at a predetermined speed through the extrusion grid plate. The improvement comprises a rotatable shredder assembly sited immediately downstream of, and in longitudinal abutment with, the extrusion grid plate, to prevent undesired escape of extruded cheese to shred each of the extruded cheese as it emerges from the extrusion grid plate to divide the extruded cheese into a plurality of discrete shreds.
By this invention, a second improvement is provided in an apparatus for forming a block of cheese into a plurality of relatively small shreds. The apparatus includes an elongated cheese chamber having longitudinally-extending side and floor surfaces for slidingly-engaging the block of cheese, an extrusion grid plate at the downstream end of the elongated cheese chamber, and ram means for forcing the block of cheese in a downstream direction at a predetermined speed through the extrusion grid plate. The improvement comprises both a rotatable shredder assembly sited immediately downstream of, and in longitudinal abutment with, the extrusion grid plate, to prevent undesired escape of extruded cheese to shred each of the extruded cheese as it emerges from the extrusion grid plate to divide the extruded cheese into a plurality of discrete shreds, and having the ram means comprise a hydraulic/pneumatic cylinder, including an upstream air chamber and a downstream hydraulic chamber, which are divided by a piston having a downstream extending piston rod connected to a cheese pusher plate assembly, and a connection from a source of air under pressure to the air chamber to initiate a power stroke, a hydraulic connection between the hydraulic chamber and a hydraulic reservoir, and a source of air under pressure to the hydraulic reservoir to initiate a return stroke.
By this invention, a third improvement is provided in an apparatus for forming a block of cheese into a plurality of relatively small shreds. The apparatus includes an elongated cheese chamber having longitudinally-extending side and floor surfaces for slidingly-engaging the block of cheese, an extrusion grid plate at the downstream end of the elongated cheese chamber, and ram means for forcing the block of cheese in a downstream direction at a predetermined speed through the extrusion grid plate. The improvement consists in the ram means comprising a hydraulic/pneumatic cylinder, including an upstream air chamber and a downstream hydraulic chamber, which is divided by a piston having a downstream extending piston rod connected to a cheese pusher plate assembly, a pneumatic connection from a source of air under pressure to the air chamber to initiate a power stroke, a hydraulic connection between the hydraulic chamber and a hydraulic reservoir, and pneumatic connection to a source of air under pressure to the hydraulic reservoir to initiate a return stroke.
By a fourth improvement of this invention, a method is provided for forming a block of cheese into a plurality of relatively small shreds of cheese. The method includes transporting a block of cheese in a downstream longitudinal direction to a predetermined, first zone. The block of cheese is urged in a perpendicular direction through the first zone into a longitudinally-extending extrusion zone. The block of cheese is extruded in a downstream direction through the longitudinally-extending zone and through a fragmentation zone. The fragmented cheese is received immediately from the fragmentation zone and, substantially-continuously thereafter, is passed through a shredding zone having a rotating shredder while substantially-simultaneously inhibiting escape of the fragmented cheese which passes through the shredding zone. The shredded cheese from the shredding zone is then recovered. The above steps are then repeated in an intermittent/continuous manner.
By a first feature of the first and second improvements of this invention, the rotatable cutter assembly includes a shredder disc support wheel, and a shredder disc which is removably, but firmly, secured to the shredder disc support wheel. By one further feature thereof, the shredder disc support wheel includes a plurality of circumferentially-spaced-apart tabs which project downwardly from the periphery thereof, and the shredder disc includes a plurality of flat circumferential areas which are adapted to be locked behind the tabs by rotation of the shredder disc until the flat circumferential areas are locked behind the tabs. By a second further feature thereof, the elongated cheese chamber which is downstream of the extrusion grid plate includes longitudinally-extending flanges, and the shredder disc support wheel is locked behind the longitudinally-extending flanges, thereby to prevent undesirable escape of the plurality of extrusions.
By a second feature of the first and second improvements of this invention, the extrusion grid plate defines a plurality of parallel, horizontal and parallel vertical knife edges constituting a plurality of rectangular parallel openings.
By a first feature of the second and third improvements of this invention, the hydraulic reservoir includes a one-way check-valved air outlet.
By a second feature of the second and third improvements of this invention, the hydraulic connection between the hydraulic chamber and the hydraulic reservoir comprises a two way hydraulic line to, and from, the hydraulic reservoir, that hydraulic connection being provided with a manually-controllable flow valve, and a one-way-check-valved hydraulic line from the hydraulic reservoir.
By a third feature of the first, the second and the third improvements of this invention, the apparatus includes a primary belt conveyor system to convey the block of cheese to an open side face of the cheese chamber, and a stop device to stop the block of cheese at the open side face of the cheese chamber.
By a first feature of this fourth improvement of this invention, the transporting step comprises transporting the block of cheese on an endless belt conveyor. By one feature thereof, the method includes the additional step of automatically and temporarily stopping the movement of the block of cheese by engaging the block of cheese against a suitable switch means.
By a second feature of this fourth improvement of this invention, the urging step comprises urging the block of cheese by applying hydraulic pressure to the block of cheese by a hydraulic cylinder.
By a third feature of this fourth improvement of this invention, the urging step is preceded by first sensing the absence of a block of cheese within the extrusion zone.
By a fourth feature of this fourth improvement of this invention, the extruding step comprises extruding the block of cheese through the extrusion zone by the steps of providing a cylinder with a pneumatic zone and a hydraulic zone which is separated by a longitudinally-movable piston; providing a connection between air under pressure and the pneumatic zone; providing an outflow connection from the hydraulic zone to an hydraulic reservoir zone, and providing an air flow connection from the hydraulic reservoir to the hydraulic zone, initiating a power stroke of the longitudinally-movable piston by introducing air under pressure into the pneumatic zone while simultaneously urging hydraulic fluid from the hydraulic zone to the hydraulic reservoir zone; and initiating a return stroke of the longitudinally-movable piston by introducing air under pressure into the hydraulic reservoir zone while simultaneously urging hydraulic fluid into the hydraulic zone.